Finally, in Fig. (REF ) we have the spectral density of induced GW today for our model, obtained from Eqs. (REF )-(REF ). We have scanned the model parameters within the ranges: \(M/m_P=[6\times 10^{-5},\, 7\times 10^{-4}]\) , \(g=[0.1,1.7]\) , \(h=[0.1,4]\)  and \(h_S=[2,4]\) . The sensitivity curves for present and planned GW detectors [1]}, [2]} are included as a reference. Also the BBN limit [3]}, that sets the amount of extra radiation that can be present at the time of formation of light nuclei. The spectrum is amplified due to modes that exit the horizon near the end of inflation, re-entering soon after during RD. Therefore, their wave numbers are in the range \(k/k_0 \simeq 10^{20}-10^{25}\) , where \(k_0=a_0 H_0\) , and this translates into the frequency range today \(f\simeq 10-10^{5}\)  Hz, with the maximal amplification \(\Omega _{GW,\,0} \approx 10^{-8}\)  close to the upper end, which leaves these waves outside the range of detection of current and near future GW experiments.
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